How many protons electrons and neutrons are in an atom of Y?

Answer 1

Yttrium atom number 39 = 39 protons.

There are two isotopes:

1. stable isotope Y89 , with relative atomic mass 89, thus (89-39) = 50 neutrons
2. unstable isotope Y88 , with relative atomic mass 88, thus (88-39) = 49 neutrons

(remember p+n=m)

Answer 2

An atom of yttrium (Y) typically has 39 protons, 39 electrons, and 50 neutrons.